Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds value by stating the data source (api.plos.org), no auth requirement, and the return fields. It does not mention pagination or rate limits, but for a read-only search tool with strong annotations, this is adequate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded: it states the action, scope, query modes, filters, return fields, and data source in two sentences. Every sentence earns its place, with no fluff or repetition of schema content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only search tool with a rich output schema, the description covers the essential context: corpus scope, query flexibility, filters, return fields, data source, and auth. It does not mention pagination or result limits, but max_results is in the schema and the output schema likely covers structure. Minor gap, not critical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all four parameters thoroughly, including examples for query syntax and enum values for sort and journal. The description adds a high-level summary of query modes and return fields but does not need to repeat parameter details. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Search'), a clear resource ('full open-access PLOS research corpus'), and enumerates the journals covered. It also lists the return fields (DOI, title, journal, authors, abstract, subjects), which distinguishes it from the sibling plos-search.article.detail. The scope is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains the query modes (free text or Solr field query) and optional filters (journal, sort), giving clear context for when to use it. It does not explicitly name alternatives or exclusions, but the sibling plos-search.article.detail is implicitly the alternative for single-article detail. The 'no auth required' note is useful operational guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.